<i18n dev> RFR: 8343777: Add since checker tests to Internationalisation modules [v2]

[Nizar Benalla]

> Can I please get a review for this PR that add tests to verify the value of `@since` tags to the Internationalisation area modules. The test is described in this [email](https://mail.openjdk.org/pipermail/jdk-dev/2024-October/009474.html). This issue is similar to JDK-8341399, JDK-8331051 and JDK-8343442.
> 
> The benefit from this is helping API authors and reviewer validate the accuracy of `@since` in their source code (and subsequently, in the generated documentation). And lessen the burden on Reviewers.
> 
> The test has been added for `java.base` and a few other modules and has helped catch some bugs before they make it to the JDK.
> 
> TIA

Nizar Benalla has updated the pull request incrementally with one additional commit since the last revision:

  add explanation to test summary, add backsticks when mentionning `@since`

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/21985/files
  - new: https://git.openjdk.org/jdk/pull/21985/files/0f60fe56..e286bbea

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21985&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21985&range=00-01

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/21985.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21985/head:pull/21985

PR: https://git.openjdk.org/jdk/pull/21985